A process of manufacturing a semiconductor device may include a process of forming a thin film on a substrate by supplying a precursor to the substrate.
However, if an insulating film is formed on a surface of a substrate that is a base of film formation, in some cases, step coverage of a thin film may decrease, or a discontinuous film having a pinhole (breakpoint) or the like may be formed. In particular, such phenomenon occurs remarkably, when a film thickness of a thin film to be formed is set to fall within, for example, a so-called thin film range of 5 Å to 100 Å, or when trenches having a high aspect ratio are formed in a surface of the substrate. The use of the discontinuous thin film, for example, in a channel of a transistor device or the like may deteriorate electrical characteristics of the device. Furthermore, the use of the discontinuous thin film as an etching stopper of an etching process using hydrogen fluoride (HF) or the like in the manufacturing process of the device may partially damage a substrate surface of a base, i.e., an insulating film formed on the substrate surface, resulting in deterioration of characteristics of the device or a production yield.
Furthermore, when an insulating film is formed on the surface of the substrate, even if a supply of a precursor to the substrate is started, in some cases, formation of a thin film on the substrate is not easily started, resulting in an increase in an incubation time. As a result, the productivity of the device decreases, and the manufacturing cost increases.